1. Field of the Invention
The present invention relates to a printing apparatus, a print control method, a computer-readable recording medium for storing a program, and a program, all of which provide an optimal printing result in accordance with a print characteristic about a paper feed direction of a printer when printing, for example, images captured by digital cameras.
2. Description of the Related Art
Recently, with the development and the widespread use of digital cameras and printers, an environment where users easily print image data using digital cameras and printers has been available. In such printers, a printable area in a normal mode is set for each feedable paper size in advance. The printers carry out processing on image data to print it in that printable area.
In general, a printer of a serial type has bad paper feed precision at the leading and trailing edges of a sheet of print paper. Accordingly, when an engine unit of the printer prints image data from an application, an area outside the printable area becomes a margin in a printout.
Recently, printers that can print beyond a printable area to provide borderless printing have been developed. In order to print an image outside the printable area, these printers slow down the paper feed at the leading and trailing edge areas of the print sheet, where the paper feed precision is degraded, compared to other areas of the print sheet.
Printers that cannot ensure the paper feed precision at the leading and trailing edge areas of the print sheet employ paper having a perforation. Tearing off the paper along the perforation after printing results in borderless printing.
Additionally, Japanese Patent Laid-Open No. 11-308470 discloses that, to prevent a major part of a print image from being missing, the major part is detected and the print size or print area is changed.
In some cases, for a printable area of such printers, a margin at the leading edge of a print sheet is different from that at the trailing edge with respect to print orientation of the print sheet. The margin at the trailing edge is usually wider than that at the leading edge. This difference is sometimes visually noticeable in a printout.
FIGS. 9 and 10 are diagrams of printout images printed by such printers. In the drawings, illustrations in line drawing represent image data.
FIGS. 9 and 10 illustrate an entire paper area 801, an effective print area 802, a border area 803, and a subject 804.
FIG. 9 shows the case where a wider margin is located at the bottom of a print image, whereas FIG. 10 shows the case where a wider margin is located at the top of the print image. As can be seen, when the margins at the top and bottom are different in printing, users generally have an impression that a wider margin at the bottom is visually less noticeable than a wider margin at the top.
When carrying out borderless printing, some printers slow down the paper feed at the leading and trailing edge areas of the print sheet where the paper feed precision is degraded so as to ensure the precision. However, if the printers fail to ensure the precision compared to that in the center area of the print sheet, some print defects, such as a little streaking, appear in printouts.
In particular, the print defects tend to occur at the trailing edge area. Although there is only a little streaking, users usually feel dissatisfied with the print quality when looking at the whole printout image. For example, FIGS. 11 and 12 show the printouts of this case.
FIGS. 11 and 12 are diagrams illustrating printout images printed by printers of this type. In the drawings, the identical elements to those illustrated and described in relation to FIGS. 9 and 10 are designated by the identical reference numerals. FIG. 11 shows the case where a degraded print quality area is located at the bottom of a print image, whereas FIG. 12 shows the case where a degraded print quality area is located at the top of the print image.
FIGS. 11 and 12 show a degraded print quality area 1001, where print defects, such as streaking or banding, occur.
As can be seen, users generally feel that a degraded print quality area located at the bottom of the print image is visually less noticeable than a degraded print quality area located at the top of the print image.
When carrying out borderless printing on paper having a perforation, a tear-off edge remains at the perforation after tearing off a paper stub. If an area where the paper feed precision is not ensured is located at either top or bottom of the print image, a perforation at only one side of paper is sufficient. However, users usually feel dissatisfied when only one tear-off edge is at one side of the paper. FIGS. 13 and 14 show the printouts of this case.
FIGS. 13 and 14 illustrate printout images printed by printers of this type. In the drawings, the identical elements to those illustrated and described in relation to FIGS. 9 and 10 are designated by the identical reference numerals.
In FIGS. 13 and 14, a tear-off edge 1201 is shown. FIG. 13 shows the case where the tear-off edge 1201 is located at the bottom of a print image, and FIG. 14 shows the case where the tear-off edge 1201 is located at the top of the print image. Users generally feel that the tear-off edge 1201 at the bottom is visually less noticeable than the tear-off edge 1201 at the top.
As described above, printers have print characteristics associated with the paper feed direction. The print characteristics have an impact on the quality of printouts. However, current print systems do not consider the print characteristics in printing, and therefore, streaking sometimes occurs at the top of the print image. A wider margin is sometimes located at the top of the print image. Also, a perforation is sometimes located at the top of the print image. These negative visual effects must be decreased.
Additionally, if, in borderless printing, a degraded print quality area including a little streaking caused by degraded paper feed precision overlaps a subject image area, the subject image exhibits the print defect. Users usually complain about this type of printout. In contrast, users have little complaint about a printout if the print defect is located outside the subject image, although the print defect still remains.
From another point of view, a frequency characteristic is one of the human visual characteristics. In general, as the frequency becomes higher, recognition of noise decreases except the case where the frequency is extremely low. If this fact is applied to a little streaking caused by degraded paper feed precision in printing, noise, such as streaking, is hard to recognize at an area having a high spatial frequency, that is, the noise is not noticeable.
As described above, the positional relationship between a degraded print quality area due to the paper feed precision of a print engine unit and a subject area produces, in a printout, a print area having the quality lower than user's expectation. As a result, total print quality of the printout does not satisfy the user, which is a problem.